Only one at-will pushes the target, and you can't use it with a polearm.
If you're a fighter, your OAs already halt the target's movement. Being able to halt it and then push it back a square can be handy, but it's not that big of a boost.
Er... does this have anything to do with Heavy Blade Opportunity?
I'm replying several things at once. And you are looking at the post a bit biased if anything (or just like picking people stuff apart trying to prove...... something?).
I'm referring to the push encounter powers/dailies. You use that ON your turn to push the mob away, when it's the mob's turn, they will have to either come after you or go thru you (unless your softies are really close to you). In either case Polearm's Gamble will trigger the OA for some damage (Reaping strike ie.), unless the mob runs away and wastes a turn doing so.
Some GMs might let you push mobs off a cliff, or into a trap/pit or many of the environmental stuff (like an open fire), if you have it pin against something like that and you, it makes a longsword+board fighter's job a lot easier. I have a group that have a fighter pinning an elite against the wizard's flaming sphere and a wall. Tide of Iron/Reaping Strike, Cloud of Dagger + the Flaming Sphere per turn dmg made short work of it. With HBO, it would much easier to pin a mob against something due to the free Tide of Iron.
It's not that big of a boost, but it's a viable option that is vital for some party make ups, let's not generalize too quickly. One man's garbage is another's man's treasure so to speak. It might not be great if you have a full party. But if it's just 1 defender with 3 softies, it can be life and death.
The last part is referring to the question about Criticals. Please read the OP and all the posts before you try to analyst something, if something isn't clear, you can just ask for clarification instead of trying to be a smart ass
